Rotary blower and timing adjustment mechanism



Dec. 24, 1968 A. J. GRANBERG ROTARY BLOWER AND TIMING ADJUSTMENTMECHANISM 2 Sheets-Sheet 1 Filed Oct. 10, 1966 MN Mm l/V VENT 0R ALBERTJ- GRANBERG B ATTORNEY Dec. 24, 1968 A. J. GRANBERG 3,417,915

ROTARY BLOWER AND TIMING ADJUSTMENT MECHANI SM Filed Oct. 10, 1966 2Sheets-Sheet 2 FTz57.5

j m VENTOR ALBERT J. GRANBERG ATTORNEY United States Patent 3,417,915ROTARY BLOWER AND TIMING ADJUSTMENT MECHANISM Albert J. Granberg, 6001Rockwell St., Oakland, Calif. 94618 Filed Oct. 10, 1966, Ser. No.585,591 2 Claims. (Cl. 230-450) ABSTRACT OF THE DISCLOSURE An apparatusfor the movement of gases utilizing a vaned rotor and an escapementrotor having a concavity for receiving the vanes of the vaned rotor. Therotors are lubricated by a self-contained system and are secured tomeshed gears having a timing adjustment mechanism permitting the rotorsto be adjusted relative to each other.

BACKGROUND OF THE INVENTION Field of the invention This inventionrelates to air and gas compressors and more particularly to a positivedisplacement rotary blower utilizing a vaned rotor and a gear drivenescapement rotor.

Description of the prior art There are many types of mechanical deviceswhich fall within the general classification of air and gas compressors.A breakdown of the class includes reciprocating compressors, rotaryblowers, centrifugal and axial fans, and turbo compressors (not tomention jet blowers or exhausters and vacuum pumps). Generally, theparticular type of gas compressor which is utilized is selectedaccording to the demands of the situation. Some of the compressors aremore suitable to moving large masses of gas at moderate increases ofpressure, while others are more efiicient for high compression ofmoderate volumes of gases and others are more eifective for highcompression of large volumes of gases. There is considerable overlappingof the different types of gas compressors whereby either of twodifierent types may suitably be used for a particular application.

Compressors may further be classified as positive displacement or asdynamic type. In the former, the machines operate by taking a quantityof gas into a closed space and by decreasing the volume of the gas Whilethe pressure is increased. In the dynamic type, the movement of the gasthrough the machine is effected either by the action of rotating vanes,which impart kinetic energy to it, or by the impingement of a stream ofair, gas, liquid or vapor, which mixes with the gas to be compressed (asin the case of jet compressors, ejectors or exhausters). The positivedisplacement compressors may be further classified into reciprocatingcompressors and rotary compressors.

The present invention is a positive displacement rotary compressor andis capable of operation over a large range of pressure increases and issuitable for use with a wide range of volumetric capacities.

In this regard, attention will be directed to rotary compressors, andthe related art, to point out the problems existing therein and thecomparative advantages of the present invention thereover. Rootsblowers, spirallobetype roots blowers, and spiraxial compressors haveintermeshing vanes which are machined over nearly the Whole of theirsurface area to very close tolerances in order to reduce slip andleakage. The machined surfaces of these types of blowers havecomplicated configurations and therefore are very expensive tomanufacture. Other related blowers which can achieve comparable pressureincreases and handle a comparable range of volumetric capacities includesliding vane type rotary compressors and centrifugal and axial fanmachines. The sliding vane "ice compressor has the disadvantage ofcontinuous contact of each of the sliding vanes with the internal wallof the easing. This creates friction which causes wear and excessiveconsumption of power. The machine is also expensive to manufacture inview of the numerous parts. Centrifugal and axial fans have thedisadvantage of being limited to moderate pressure increases and of notbeing adaptable to widely variable volumetric outputs from the samemachine. They are also usually quite expensive to manufacture.

SUMMARY OF THE INVENTION The present invention provides a solution toeach and all of these problems by providing a positive displacementdevice which has only a minimum of machined portions as compared withthe roots type and spiraxial blowers. While it is yet a positivedisplacement device, it is also of relative simple construction wherebyit can be made quite large for moving very large quantities of gas suchas can be moved by centrifugal or axial fans and without thedisadvantage of being limited to relative low to moderate pressureincreases.

Briefly, the present invention is a positive displacement blower whichcomprises a blower housing defining an interior chamber having inlet andoutlet ports disposed on generally opposite sides of the housing. Firstand second end cover plates are sealed to the housing and a vaned rotoris journalled in the end cover plates. The rotor has a generallycylindrical body with a multiplicity of vanes secured to the peripheryof the body which seal with the housing and the end cover plates. Agenerally cylindrical escapement rotor is journalled in the end coverplates and it has at least one concave portion extending along thecylindrical face thereof. The escapement rotor intermeshes with thevaned rotor and continuously seals with the end cover plates and thehousing and the vaned rotor thereby preventing bypassage of gas from theinlet port to the outlet port. The concave portion of the escapementrotor is formed as a generated surface and seals with the vanes of thevaned rotor as they pass the escapement rotor during operation of theblower. The blower also includes an escapement rotor driving means forrotating the escapement rotor relative to the vaned rotor whereby eachof the rotor vanes seals with the concave portion of the escapementrotor while traveling between the outlet and inlet ports and theescapement rotor seals with the vaned rotor when the vanes are notpassing the escapement rotor.

Thus, the present invention provides a positive displacement blowerwhich can either be fabricated of a relatively lightweight andinexpensive construction, such as sheet metal, for use as a largecapacity blower, for large building heating, ventilating and airconditioning systems, or the blower can be a finely constructed devicefor use in relatively small capacity high pressure applications such asa high pressure pump or as a blower for an internal combustion engine.

OBJECTS OF THE INVENTION It is, therefore, an important object of thepresent invention to provide a versatile blower which can be utilizedfor a large range of pressure and volumetric capacity applications.

Another object of the present invention is to provide a gas compressorin which a novel escapement mechanism is utilized to seal between theinlet and outlet ports to prevent leakage in the blower.

A further object of the present invention is to provide a new and novelblower for achieving positive displacement gas compression from a deviceof relatively simple construction as compared with comparable blowers.

Other objects and advantages of the present invention '3 become apparentwhen the blower is considered in conjunction with the accompanyingdrawings.

DESCRIPTION OF THE DRAWINGS FIGURE 1 is a plan view of a preferredembodiment of the gas compressor comprising the present invention withan end cover removed;

FIGURE 2 is a side elevation in section of the gas compressor takenalong lines 22 of FIGURE 1;

FIGURE 3 is a partial plan view of the gas compressor showing the vanedrotor just as one vane enters and begins to seal with the concavesection of the escapement rotor;

FIGURE 4 is a plan view of the meshed spur timing gears forming aportion of the escapement mechanism rotor driving means;

FIGURE 5 is an exploded perspective view of the larger spur timing gearand its associated elements.

DESCRIPTION OF THE PREFERRED EMBODIMENT Reference is made to thedrawings for a detailed description of a preferred embodiment of theinvention. FIGURE 1 presents the basic construction of the invention.The meter housing 11 defines an interior chamber of uniform crosssection which can be considered a pair of overlapping different sizecircles, or the chamber can be considered as a pair of intermeshedparallel cylindrical chambers 13, 15 of different diameter. The interiorchamber defines a continuous wall of adjoining partially cylindricalwall sections 17, 19.

Inlet and outlet ports 21, 23 are disposed on opposite sides of thehousing 11 and communicate therethrough with that portion of theinterior chamber developed by the larger of the overlappingcross-sectional circles in the larger of the cylindrical chambers 13.

The ends 25 of the meter housing are formed for mating with first andsecond end cover plates 27, 29. These plates are secured to the housing,in the preferred embodiment, by means of bolts 31 and flanges 33. Theplates are preferably sealed to the housing by O-rings 35 or othersimilarly functioning seals which permit the machined surfaces of thehousing and end cover plates to establish direct contact between eachother so that the internal clearances are accurately established.

The end cover plates are formed for supporting rotating shaft bearings37 and for containing lubricant for them. The bearings are supported inmachined-out hearing supports 39 and the lubricant is contained at oneside of the blower by means of shaft end cover caps 41 on the first endcover plate and on the other side of the blower in a reservoir 43 by acover plate 45 which secures to the retaining walls 47 formed on thesecond end cover plate 29.

A vaned rotor 49 is concentrically disposed in the larger of the housingchambers 13 and is keyed 51 to a concentricaly disposed drive shaft 53which is journalled 37 in the end cover plates. The shaft has a passage35 extending axially into the end thereof from the first end cover plate27 and which communicates with the lubricant reservoir under the shaftend cover cap 41. The other end of the passage has a connecting passage57 extending at right angles to the concentric passage 55 for permittingthe flow of lubricant through the shaft.

The vaned rotor 49 is formed with a peripheral shell 59 defining thecylindrical external surface thereof and it has a central hub section 61which engages the drive shaft '53. A supporting web 63 extends betweenthe central hub 61 and the peripheral shell 59 in either or both of aflange (FIGURE 2) or spoke configuration (FIG- URE 1). Both types ofsupporting webs are utilized in the preferred embodiment. Duringoperation of the blower, the edges 65 of the peripheral shell 59 sealwith the end cover plates 27, 29 by means of close tolerance fits.

The vaned rotor 49 has two rectangular vanes 67 secured to the generallycylindrical body at diametrically opposed positions on the peripheralshell 59. The vanes are disposed as radial extensions of the circularbody and the outer ends 69 thereof have a generally cylindricalconfiguration. The outer ends of the vanes 67 seal with the wall 17 ofthe larger cylindrical chamber of the housing while the edges 71 of thevanes seal with the end cover plates 27, 29. In the preferredembodiment, the vanes are made removable from the body of the rotor topermit easier machining of the parts of the rotor assembly.

A generally cylindrical escapement rotor 73 is journalled in the endcover plates 27, 29 on a hollow rotor shaft 75 and is concentricallydisposed within the smaller of the cylindrical chambers 15 in sealingrelation with the wall 19 thereof. The passage 77 permits the free flowof lubricant between the reservoirs 43, 45 in the end cover plates.

The escapement rotor 73 has a partially cylindrical concave portion 79formed as a generated curve which extends the length of the cylindricalsurface parallel the axis of the rotor. The concavity 79 is of a depthequal to the length of the extension or the length of the projection ofthe vanes 67 from the cylindrical portion of the vaned rotor body. Thisdepth is measured from the projected circumference of the escapementrotor radially inward. These proportions permit continuous sealing ofthe vanes 67 with the concave portions 79 when the vanes pass theescapement rotor during operation. The cylindrical surface of theescapement rotor continuously seals wtih the cylindrical surface of thevaned rotor when the vanes are not sealing with the concave portion ofthe escapement rotor.

For proper sealing of the escapement rotor 73 with the vaned rotor 49,and to provide the positive displacement characteristics of the blower,it is necessary that a portion of the external surface of the escapementrotor be in sealed relation with the vaned rotor at all times. Thisprovides a continuous seal between the inlet and outlet ports 21, 23 andprevents leakage therebetween. It is effected either by the vanes of thelarger rotor sealing with the generated concavity of the escapementrotor or by the two external cylindrical surfaces of the rotors beingdisposed in a sealed relationship.

The escapement rotor 73, like the vaned rotor 49, in order to keep itlightweight, is formed with a peripheral shell 81 which defines theexternal surface of the generally cylindrical body. The shell issupported by web structure 83 which extends from the central core 85 tothe peripheral shell 81. The web structure actually forms the wall ofthe generated concavity. The escapement rotor 73 can be keyed to therotor shaft 75 to rotate with it or the shaft formed as part of therotor. The edges or ends 89 of the escapement rotor continuously sealwith the end cover plates 27, 29. The external cylindrical surface ofthe escapement rotor continuously seals with cylindrical wall 19 of thesmaller chamber 15 of the housmg.

A gearing means is provided for driving the escapement rotor 73 at twicethe angular velocity of the vaned rotor 49 whereby each of the rotorvanes 67 seals with the concave portion 79 of the escapement rotor whiletravelling between the outlet and inlet ports 21, 23. The gearing meansincludes a pair of meshed spur gears 91, 93. The first or the larger ofthe spur gears 91 has a diameter twice as large as the second of thespur gears 93 and is interconnected with the vaned rotor 49 for equalangular velocity in the same direction therewith. This is most easilyaccomplished as shown in the preferred embodiment by securing the spurgear to the drive shaft 53 of the blower.

The second or the smaller of the gears 93 is adjustably interconnectedwith the escapement rotor 73 to effect equal angular velocity of therotor and the gear. The adjustment is effected by providing a projectingflange 95 on the spur gear 93 which mates with an independent matchingcap 97 which is keyed 99 to the shaft 75 of the rotor. A clearance 101is provided between the opposing surfaces of the flange 95 and the cap97 to permit cap screws 103 to rotate the spur gear with respect to thecap a couple of degrees in either direction. This permits a timingadjustment of the escapement rotor 73 for proper meshing relationshipwith the vanes 67 of the vaned rotor.

The larger of the spur gears 91 is secured to the drive shaft 53 by aset screw 105 and has a projecting hub 107 which has an oil hole 109extending therethrough which aligns with the connecting passage 57 inthe drive shaft.

A spring loaded oil seal element 111 engages with the projecting hub 107of the larger spur gear 91 by means of interrneshing sprags 113 androtates with the spur gear. The element 111 seals against a sealing ring115 supported in the lubricant reservoir cover plate 45. This preventsleakage from the lubricant chamber along the drive shaft.

The lubricant for all of the bearings is kept in a single reservoir andthe spur gears operate immersed in the lubricant. The lubricant reachesthe bearings under the end cover caps by means of the passages in therotor shafts. The oil must pass through the connecting passage in theprojecting flange on the larger spur gear to reach the hollow passage inthe drive shaft. It is therefore necessary to be careful to align thosepassages during assembly of the meter.

In considering the preferred arrangement of the working relation of theparts of the invention, the housing 11 can be divided into quadrants.The inlet 21 and the outlet port 23 are disposed in two adjacentquadrants for communicating through the housing wall with the largerinterior chamber 13. The escapement rotor is disposed in the smallercylindrical chamber between the ports located symmetrically on theadjacent quadrants division line. A partitioned generally semicircularpassage is formed opposite the escapement rotor between the end coverplates 27, 39, the housing wall 19, and the outer surface of thegenerally cylindrical body of the vaned rotor. The compartment extendsin a semicircle of generation greater than 180 degrees. This is so thatat least one of the rotor vanes always seals the semicircular passagebetween the ports at all times to prevent leakage. With only two blades,the passage must be at least equal to, and practically, greater than 180degrees of generation to permit the transition of sealing from one bladeto the other.

The vanes of the rotor seal with the end cover plates and the wall ofthe housing by a close tolerance fit with the sealing surface of each ofthese elements. The close mating but noncontacting relation of the partspermits a slidable sealing relation which effectively prevents leakagewithout wear or drag.

In operation, the gase to be compressed enters into the blower throughthe inlet port and travels in a path tangential to the interior wall 17of the larger cylindrical chamber 13 of the housing.

More than two vanes can be used on the vaned rotor if the escapementrotor is driven at a higher rate of angular velocity relative to thevaned rotor or if additional generated concave portions are provided inthe cylindrical surface of the escapement rotor. If more than two vanesare provided on the vaned rotor, the passage can be of a lesser angle ofgeneration than 180 degrees, but the passage must extend around theinterior wall sufliciently far to always permit one blade to seal itcontinuously.

The blower of the present invention has many advantages as compared withthe related art. The new and novel design permits relatively largecapacity blowers to be fabricated from a lightweight construction. Thelow weight of the rotating parts, coupled with the frictionless sealsbetween the rotors and the housing, reduces the energy required to drivethe mechanism. Due to the fact that there is no metallic contact betweenthe parts for effecting the seals, the life expectancy of the blower isextended over that of comparable machines. The bearings are lubricatedfrom a single reservoir by means of the hollow shafts while the timinggears operate immersed in the oil reservoir for a long life and lowmaintenance. The design of the rotors permits their surfaces to rollwith each other without any sliding or relative motion. The blower canbe operated in either direction with equal efficiency.

The device of the present invention is also suitable as a liquid pump.In this regard, it is especially or particularly adaptable for thepumping of butane or other nonlnbricating liquids. This is due to thefact that there are no metal-to-metal seals and all of the lubricationis provided from a reservoir within the meter itself.

It will be apparent from the foregoing description of the invention, inits preferred form, that it will fulfill all of the objects attributablethereto. While it has been illustrated and described in considerabledetail, the protection is not to be limited to such details as have beenillustrated and described, except as may be necessitated by the appendedclaims.

I claim:

1. A positive displacement blower comprising a housing defining aninterior chamber of uniform cross section of overlapping different sizedcircles,

inlet and outlet ports disposed on opposite sides of said housingadjacent the smaller of said circles communicating with a portion of thechamber defined by the larger of said circles,

first and second end cover plates sealed to said housing and adapted tocontain lubricant,

a vaned rotor having a generally cylindrical body disposed concentric tothe larger of said cross-sectional circles and having two vanes securedat diametrically disposed positions on the periphery of said rotor, saidvanes sealing with said housing and said end cover plates,

a generally cylindrical escapement rotor having a concave portionextending along the cylindrical face thereof, said escapement rotordisposed concentric to the portion of the chamber defined by the smallerof the cross-sectional circles and intermeshing with said vaned rotorand continuously sealing with said end cover plates, said housing, andsaid vaned rotor, said concave portion formed of a generated curve toseal with said vanes as they pass said escapement rotor during operationof the compressor,

said rotors mounted on shafts journalled in said end cover plates andhaving passages to permit free flow of lubricant therethrough betweensaid end cover plates,

escapement rotor driving means including meshed spur gears secured tosaid rotor shafts for rotating said escapement rotor at twice theangular velocity of said vaned rotor whereby each of said rotor vanesseals with the concave portion of said escapement rotor while travellingbetween said outlet and inlet ports,

a spring loaded oil seal element engaged with the gear secured to thepower input shaft of said blower, said seal rotated by means of meshedprojecting sprags secured to said gear and said seal respectively,

a projecting flange on the other of said gears,

a cap keyed to one of said rotor shafts and adjustably secured to saidprojecting flange and providing a clearance between the opposingsurfaces of the flange and the cap to permit a few degrees of rotationof the gear with respect to the cap.

2. A positive displacement blower comprising a housing defining a pairof intermeshed parallel cylindrical chambers of different diameterhaving continuous adjoining partially cylindrical interior wallsections,

first and second end cover plates sealed to said housing at the ends ofsaid cylindrical chambers and being adapted for supporting rotatingshafts and containing lubricant for said shafts, V

inlet and outlet ports disposed on opposite sides of said housing andcommunicating therethrough with the larger of said cylindrical chambersadjacent the smaller cylindrical chamber,

a drive shaft disposed concentric to the larger of said chambers andjournalled in said end cover plates and projecting through one of them,

a vaned rotor having a generally cylindrical body concentrically securedto said drive shaft and having two vanes disposed at diametricallyopposed positions on the periphery of said rotor sealing with the wallof said chamber and said end cover plates, said rotor being formed witha peripheral shell defining the external surface of said cylindricalbody and a central hub section secured to said drive shaft and asupporting web extending between said central hub and said peripheralshell, the edges of said peripheral shell sealing with said end coverplates,

a rotor shaft journalled in said end cover plates concentric to thesmaller of said cylindrical chambers, said drive shaft and said rotorshaft having passages therethrough for permitting free flow of lubricantbetween said end cover plates,

a generally cylindrical escapement rotor adjustably secured to saidrotor shaft and having a partially cylindrical concave portion extendingthe length of the cylindrical surface thereof formed of a generatedcurve, said rotor formed with a peripheral shell defining the externalsurface of said generally cylindrical body and a central hub sectionsecured to said rotor shaft and a supporting web extending between saidcentral hub and said peripheral shell, the edges of said peripheralshell sealing with said end cover plates, the peripheral surface of saidrotor being in continuous sealing relation with the walls of the smallerof said cylindrical chambers, said concave portion being of a depthequal to the length of the projection of said vanes from the cylindricalportion of said vaned rotor body to permit continuous sealing of saidvanes with said concave portion when said vanes pass said escapementrotor and for the cylindrical surface of said escapement rotor to sealwith the cylindrical surface of said vaned rotor when said vanes are notsealing with said concave portion,

gearing means for driving said escapement rotor at twice the angularvelocity of said vaned rotor whereby each of said rotor vanes seals withthe concave portion of said escapement rotor while travelling betweenthe outlet and inlet ports, said gearing means including a pair ofmeshed spur gears, the first of said gears having a diameter twice aslarge as the second of said gears and interconnected with said vanedrotor for equal angular velocity in the same direction and said secondgear adjustably interconnected with said escapement rotor for equalangular velocity in the same direction therewith by means of a cap keyedto one of said rotor shafts and adjustably secured to said projectingflange and providing a clearance between the opposing surfaces of theflange and the cap to permit a few degrees of rotation of the gear withrespect to the cap, and

a spring loaded oil seal element on the shaft which projects throughsaid end cover plate, said seal rotated by means of meshed projectingsprags secured to said gear and said seal respectively.

References Cited UNITED STATES PATENTS 866,434 9/1907 Colldeweih 918 1971,660 10/1910 Brewster 230 2,177,976 10/ 1939 Brauer 91-81 2,963,98112/ 1960 Hanatsuka 103-125 3,299,825 1/ 1967 Bjorndal 103126 FRED C.MATTERN, JR., Primary Examiner. WILBUR J. GOODLIN, Assistant Examiner.

US. Cl. X.R. 230- 207

